755  
FXUS02 KWBC 022101  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
401 PM EST WED MAR 02 2022  
 
VALID 12Z SAT MAR 05 2022 - 12Z WED MAR 09 2022  
 
...HEAVY SNOW POTENTIAL OVER THE NORTHERN PLAINS THROUGH UPPER  
GREAT LAKES AND POSSIBLY INTO NORTHERN NEW ENGLAND DURING THE  
WEEKEND...  
 
...HEAVY RAINFALL POTENTIAL FROM THE MID-LOWER MISSISSIPPI VALLEY  
INTO TENNESSEE/OHIO VALLEYS LATE WEEKEND INTO EARLY NEXT WEEK...  
   
..OVERVIEW
 
 
GUIDANCE MAINTAINS THE FORECAST OF A POSITIVELY TILTED MEAN TROUGH  
FROM CANADA INTO THE WESTERN U.S., BETWEEN A STRONG RIDGE OVER THE  
EASTERN PACIFIC AND ANOTHER RIDGE THAT MEANDERS OVER OR NEAR THE  
SOUTHEASTERN GULF OF MEXICO. THIS CONFIGURATION WILL SUPPORT AN  
ACTIVE WEATHER PATTERN, WITH A COUPLE EPISODES OF PRECIPITATION  
OVER PARTS OF THE WEST AND LIKELY ONE OR MORE AREAS OF SIGNIFICANT  
RAIN AND SNOW OVER SOME AREAS OF THE CENTRAL AND EASTERN U.S. THE  
SYSTEM HAVING HIGHEST CONFIDENCE WILL TRACK NORTHEASTWARD FROM THE  
CENTRAL ROCKIES/PLAINS INTO THE UPPER GREAT LAKES THIS WEEKEND  
WITH A CORRESPONDING BAND OF SNOW FROM THE NORTH-CENTRAL HIGH  
PLAINS THROUGH THE UPPER GREAT LAKES AND POSSIBLY NORTHERN NEW  
ENGLAND. A TRAILING UPPER LOW REACHING THE WEST SHOULD ULTIMATELY  
PRODUCE ANOTHER SURFACE WAVE, ALONG THE FIRST SYSTEM'S COLD FRONT,  
THAT TAKES A SOMEWHAT FARTHER SOUTHEAST TRACK BUT WHOSE DETAILS  
ARE OTHERWISE LESS CERTAIN. THIS EVOLUTION MAY SUPPORT AN AREA OF  
HEAVY RAINFALL OVER PARTS OF THE EAST-CENTRAL U.S. LATE WEEKEND  
INTO EARLY NEXT WEEK AND POSSIBLY SOME WINTRY WEATHER ON THE COLD  
SIDE OF THE SECOND WAVE. BELOW NORMAL TEMPERATURES INITIALLY OVER  
THE WEST AND NORTHERN PLAINS WILL EXPAND INTO THE REST OF THE  
CENTRAL U.S. WHILE FRONTAL PROGRESSION WILL GRADUALLY TRIM THE  
WESTERN EXTENT OF MUCH ABOVE NORMAL TEMPERATURE ANOMALIES OVER THE  
CENTRAL/EASTERN STATES.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
AFTER SOME SIGNIFICANT VARIABILITY AND SPREAD IN RECENT DAYS,  
GUIDANCE OVER THE PAST DAY APPEARS TO BE STABILIZING WITHIN THE  
STRONGER HALF OF THE PRIOR ENVELOPE FOR STRENGTH AS THE INITIAL  
SURFACE LOW AND SHORTWAVE REACH THE UPPER GREAT LAKES EARLY SUNDAY  
WHILE MAINTAINING DECENT CONTINUITY FOR TRACK, WITH JUST A BIT OF  
EAST/WEST SPREAD. CONSENSUS CONTINUES TO SHOW BETTER DEFINITION OF  
THE INITIAL LOW AS IT CONTINUES NORTHEASTWARD INTO THE CANADIAN  
MARITIMES BY SUNDAY MORNING, ALONG WITH A SLIGHT SHIFT OF THE  
SHORTWAVE AND COLD FRONT SOUTHWARD OVERALL COMPARED TO THE  
PREVIOUS CYCLE. THE PATTERN REMAINS COMPLEX BEHIND THE LEADING  
WAVE, AS A LIKELY CLOSED UPPER LOW IN THE WEST OVER THE WEEKEND  
EJECTS EAST EARLY IN THE WORKWEEK, BUT IS MUDDLED BY SHORTWAVE  
ENERGY DROPPING INTO THE WEST IMMEDIATELY BEHIND IT AND ALSO  
SEPARATE UPPER TROUGHING THAT DROPS INTO THE NORTHERN PLAINS AND  
VICINITY. WHILE A COLD FRONT IS LIKELY AHEAD OF THE MEAN TROUGH,  
GUIDANCE CONTINUES TO WAFFLE WITH PLACEMENT OF WAVES OF LOW  
PRESSURE ALONG IT. THE 00Z ECMWF AND 06Z GEFS MEANS SHOWED A  
POSITION FOR THE LOW NEAR THE INDIANA/OHIO BORDER EARLY MONDAY,  
WITH MORE VARIABILITY IN POSITION AMONG DETERMINISTIC MODELS, BUT  
THE NEWER 12Z MODELS HAVE STARTED TO CLUSTER BETTER APPROXIMATELY  
IN THAT LOCATION. THEN UPSTREAM, THERE ARE AMPLE DIFFERENCES IN  
THE DETAILS OF THE PATTERN BY TUESDAY-WEDNESDAY GIVEN MULTIPLE  
INTERACTING LOW PREDICTABILITY SHORTWAVES. THE ECMWF AND CMC HAVE  
BEEN PERSISTENT IN HOLDING TROUGHING BACK ACROSS THE SOUTHWEST IN  
A VERY POSITIVELY TILTED FORM, WHILE GFS RUNS HAVE SHOWED MORE  
PROGRESSIVE TROUGHING. THE 00Z EC/CMC PATTERN IS ALMOST OUTSIDE  
THE ENVELOPE OF ENSEMBLE MEMBERS WITH THIS SOUTHWEST TROUGH. THUS  
SOMEWHAT PREFERRED THE GFS SOLUTIONS ALONG WITH THE "MIDDLE  
GROUND" EC MEAN. NEWER 12Z GUIDANCE SHOWS A FASTER TROUGH IN THE  
EC/CMC AND SLOWER IN THE GFS, SO PERHAPS A CONSENSUS IS BEING  
REACHED, AT LEAST TEMPORARILY.  
 
EARLY IN THE PERIOD A BLEND OF THE 00Z/06Z OPERATIONAL GFS, ECMWF,  
AND CMC MODELS PROVIDED A REASONABLE STARTING POINT FOR THE  
FORECAST. THE 00Z UKMET WAS AN OUTLIER WITH PORTIONS OF THE  
PATTERN, WITH A SLIGHTLY EASTERN TRACK OF THE MAIN CLOSED UPPER  
LOW IN THE WEST COMPARED TO CONSENSUS, BUT MORE SO WITH MUCH  
STRONGER UPSTREAM ENERGY COMING INTO WESTERN CANADA AND  
SUPPRESSING THE EASTERN PACIFIC RIDGE BY MONDAY. THE ENSEMBLE  
MEANS DID HAVE A HINT OF THIS, AND THE 00Z GFS WAS MOST LIKE THEM,  
BUT NOT TO THE EXTREME OF THE UKMET. THE UKMET SEEMED REASONABLE  
ACROSS THE EAST THOUGH. THEN AS THE PERIOD PROGRESSED, INTRODUCED  
AND INCREASED WEIGHTING OF THE ENSEMBLE MEANS, PARTICULARLY THE EC  
MEAN THAT SHOWED A DEEPER TROUGH IN THE SOUTHWEST BUT NOT TO THE  
EXTREME OF THE OPERATIONAL EC AND CMC.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
ACROSS THE WEST, THE LEADING SYSTEM EMERGING INTO THE PLAINS MAY  
PRODUCE SOME CENTRAL ROCKIES SNOW EARLY IN THE WEEKEND WHILE THE  
SYSTEM IMMEDIATELY BEHIND IT SPREADS RAIN AND HIGHER ELEVATION  
SNOW PRIMARILY FROM THE SIERRA NEVADA INTO THE WASATCH AND CENTRAL  
ROCKIES. EXPECT GENERALLY LIGHT TO MODERATE TOTALS BUT WITH SOME  
LOCALLY HEAVIER TOTALS POSSIBLE. THERE IS CONTINUED POTENTIAL FOR  
ANOTHER SYSTEM TO SPREAD MOSTLY LIGHT TO MODERATE PRECIPITATION  
INTO THE NORTHWEST/NORTHERN ROCKIES DURING THE FIRST HALF OF NEXT  
WEEK BUT WITH LESS THAN IDEAL CONFIDENCE IN THE DETAILS.  
 
TO THE EAST OF THE ROCKIES, THE LEADING SYSTEM FORECAST TO TRACK  
FROM THE CENTRAL PLAINS THROUGH UPPER GREAT LAKES DURING THE  
WEEKEND SHOULD SPREAD WINTRY PRECIPITATION FROM THE NORTH-CENTRAL  
HIGH PLAINS INTO THE UPPER GREAT LAKES AND EVENTUALLY NEW ENGLAND  
(WHERE A CHANGEOVER TO RAIN MAY OCCUR). HIGHEST PROBABILITY OF  
SIGNIFICANT SNOWFALL REMAINS JUST TO THE NORTHWEST OF THE SURFACE  
LOW TRACK, WITH INCREASING CHANCES OVER THE NORTHERN PLAINS AND  
CONTINUED CHANCES OVER THE UPPER MIDWEST. THE STORM MAY BE STRONG  
ENOUGH TO PRODUCE SOME BRISK WINDS, WITH SPECIFICS TO BE RESOLVED  
IN COMING DAYS. RAINFALL OF VARYING INTENSITY WILL BE POSSIBLE  
OVER THE REST OF THE CENTRAL/EAST-CENTRAL U.S. AHEAD OF THE  
TRAILING COLD FRONT. EMBEDDED THUNDERSTORMS COULD BE SEVERE IN THE  
MID-MISSISSIPPI VALLEY ON SATURDAY AND THE LOWER MISSISSIPPI  
VALLEY ON SUNDAY PER THE LATEST STORM PREDICTION CENTER EXTENDED  
OUTLOOK. GUIDANCE IS STILL SHOWING POTENTIAL FOR HEAVIER RAINFALL  
WITHIN AN AREA FROM THE SOUTHEASTERN PLAINS INTO THE  
OHIO/TENNESSEE VALLEYS BY SATURDAY NIGHT/SUNDAY INTO EARLY NEXT  
WEEK, AND THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL IN PLACE IN  
WPC'S NEWLY EXPERIMENTAL DAY 5 OUTLOOK. THIS THREAT CORRESPONDS TO  
SLOWER PROGRESSION OF THE TRAILING FRONT AS IT BECOMES MORE  
ALIGNED WITH FLOW ALOFT, INTERACTION WITH LOW LEVEL GULF MOISTURE,  
AND THE POSSIBILITY OF ONE OR MORE WAVES THAT WOULD PROVIDE ADDED  
RAINFALL FOCUS. THE NORTHWESTERN FRINGE OF THIS MOISTURE SHIELD  
SHOULD CONTAIN SOME WINTRY WEATHER, LIKELY ALONG AN AXIS SOMEWHAT  
SOUTHEAST OF THE FIRST EPISODE. SPECIFICS WILL DEPEND ON  
LOWER-CONFIDENCE WAVE DETAILS WHICH WILL TAKE ADDITIONAL TIME TO  
RESOLVE. ONE CHANGE WITH THIS FORECAST CYCLE WAS MODEL GUIDANCE  
TAKING THE BULK OF THE RAINFALL EASTWARD RATHER THAN SOUTHWARD AS  
THE COLD FRONT PROGRESSES, SO TRENDED DOWN WITH QPF OVER THE GULF  
COAST STATES, BUT THIS IS STILL SUBJECT TO CHANGE.  
 
COLDER AIR INITIALLY OVER THE WESTERN U.S. AND NORTHERN PLAINS AND  
SPREADING OVER THE REST OF THE CENTRAL U.S. INTO EARLY NEXT WEEK  
SHOULD YIELD A BROAD AREA OF TEMPERATURES THAT ARE 5-15F BELOW  
NORMAL. BEST POTENTIAL FOR LOCALLY COLDER ANOMALIES, ESPECIALLY  
FOR HIGHS, WILL BE OVER THE NORTHERN/CENTRAL HIGH PLAINS. LEADING  
WARM SECTOR AIR, INITIALLY FOCUSED OVER THE CENTRAL-SOUTHERN  
PLAINS AND SOUTHERN TWO-THIRDS OF THE EAST ON SATURDAY, WILL  
BECOME MORE PRONOUNCED OVER THE EAST BY SUNDAY-MONDAY WHEN PLUS  
10-25F ABOVE NORMAL ANOMALIES FOR HIGHS AND LOCALIZED HIGHER  
ANOMALIES FOR MORNING LOWS MAY CHALLENGE DAILY RECORDS FOR  
HIGHS/WARM LOWS. HIGHEST CONCENTRATION OF RECORD HIGHS MAY BE OVER  
THE SOUTHEAST WITH A FEW RECORD HIGHS ELSEWHERE, SUCH AS THE  
MID-ATLANTIC. COVERAGE OF RECORD WARM LOWS MAY BE BROADER. AFTER  
MONDAY, FRONTAL PROGRESSION WILL INCREASINGLY CONFINE THE WARMTH  
TO THE SOUTHEAST, WITH RECORD WARMTH REMAINING POSSIBLE IN FLORIDA.  
 
TATE/RAUSCH  
 
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE MIDDLE/LOWER MISSISSIPPI  
VALLEY, THE SOUTHERN PLAINS, THE OHIO  
VALLEY, AND THE TENNESSEE VALLEY, SUN-MON, MAR 6-MAR 7.  
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL ROCKIES, THE  
NORTHERN/CENTRAL PLAINS, THE GREAT LAKES,  
AND THE UPPER MISSISSIPPI VALLEY, SAT, MAR 5.  
- SEVERE WEATHER ACROSS PORTIONS OF THE MIDDLE/LOWER MISSISSIPPI  
VALLEY, THE SOUTHERN PLAINS, AND  
THE TENNESSEE VALLEY, SUN, MAR 6.  
- SEVERE WEATHER ACROSS PORTIONS OF THE CENTRAL PLAINS, AND THE  
UPPER/MIDDLE MISSISSIPPI VALLEY,  
SAT, MAR 5.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE PACIFIC  
NORTHWEST, THE OHIO VALLEY, AND THE  
TENNESSEE VALLEY.  
- FLOODING LIKELY ACROSS PORTIONS OF THE NORTHERN ROCKIES AND THE  
NORTHERN GREAT BASIN.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
ROCKIES, AND THE PLAINS, SUN-MON,  
MAR 6-MAR 7.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE  
NORTHERN/CENTRAL PLAINS, AND THE NORTHERN  
ROCKIES, SAT-SUN, MAR 5-MAR 6.  
- ENHANCED WILDFIRE RISK ACROSS PORTIONS OF THE CENTRAL PLAINS AND  
THE SOUTHERN PLAINS, SAT, MAR 5.  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, WINTER WEATHER OUTLOOK PROBABILITIES  
AND HEAT INDICES ARE AT:  
 
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 

 
 
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